The present invention relates to traffic information collection, and more specifically, to reducing cost of transmitting accurate, real-time traffic data to a central server via a cellular network, by using data aggregation, based on quantum transmission cost, and a form of random sampling that is based on priorities of the traffic network links, to determine whether a specific data packet is to be transmitted.
FIG. 1 demonstrates two relatively recent communications systems for vehicles on roadways, typically with at least some aspects still under development. A first communication system permits individual vehicles 102 to transmit data to a central server 104 via a backhaul, such as a cellular network 106, using On Board Units (OBUs) 108 or other equivalent devices.
Collecting traffic data in this manner is not new, since Intelligent Transport Systems (ITS) have been in various stages of development and implementation in various countries. Such traffic information systems are typically based on a plug-and-play, in-vehicle platform utilizing OBUs 108 that link vehicles with the transportation infrastructure 104 using cellular links 110. Some ITS systems permit a two-way transmission by which vehicles can receive information, typically used conventionally for such features as providing safety warnings and traffic information to drivers. In a preferred exemplary embodiment of the present invention, the OBU is capable of Global Positioning System (GPS) interface, to determine the current location of the vehicle in which the OBU is installed.
A second recent vehicular communication system depicted in FIG. 1 is the vehicle-to-vehicle (V2V) intercommunication system 112. This V2V system permits vehicles to “talk” to each other and has been under development for several years by various automobile manufacturer. In some versions, V2V permits ad hoc networks to form among vehicles, as intended to help drivers overcome blind spots, avoid accidents, etc. A V2V standard is close to being approved in the United States, with discussion to make it mandatory by 2017.
The basic approach of acquiring traffic information via technologies such as ITS has been considered as attractive compared to other alternatives, due to its flexibility and potentially very wide coverage with essentially no additional infrastructure requirement.
However, the present inventors have recognized that potentially high cost can be incurred in the conventional ITS-like systems due to the following challenges:                Sufficient amount of data needs to be collected such that the traffic information derived on the central server achieves the required accuracy and network coverage.        The collected traffic data must be transmitted to the server with low latency, such that the derived traffic information satisfies a given real-time requirement.        Each cellular transmission is charged based on a minimum charging unit (e.g. $x per y-KB). To minimize cost, it would be ideal if each OBU would transmit collected data in batches, aligning the batch size with the minimum charging unit. However, waiting for a full batch of data may result in excessive delay, affecting the real-time requirements.        
The present invention provides a solution to these newly-recognized problems recognized as due to conflicting aspects in making network traffic data reports in management systems using reports from vehicles.